I made two separate starters of wyeast 2278 Bohemian Lager and they both smell strongly of diacetyl. The starters were kept at about 68 degrees. I just brewed the batch and will be ready to pitch the yeast in a few hours. I am not that familiar with lager brewing. Is it ok to use this yeast?

IIRC that one is a good diacetyl producer. You need to pitch a lot of it a little below fermentation temp, manage the temps during fermentation, and do a diacetyl rest or a long lagering time. The yeast will reasorb the diacetyl when they are done fermenting given time. With a starter you have not given them time to reabsorb. I also recommend yeast nutrient in the end of the boil.

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Jeff RankertAnn Arbor Brewers GuildAHA Governing Committee BJCP NationalHome-brewing, not just a hobby, it is a lifestyle!

I've never worried too much about how a well handled yeast starter smells. If it is healthy and not made with questionable sanitation practices it will treat you right. Just follow proper fermentation protocol.

Agreed - you are making yeast - not beer, so you want healthy yeast as the end result. I don't think the same rules apply as to making beer. I will post one caveat - my palate is weak as to diacetyl and DMS. Others may say that they can perceive either aspect where I just don't.